Momentary contact switch



June 20, 1961 c, FYFE MOMENTARY CONTACT SWITCH 2 Sheets-Sheet 1 FiledMay 6, 1959 .E F EF 0 V T m 3 m 0 r C .7 8- H 3 June 20, 1961 FYFE2,989,600

MOMENTARY CONTACT SWITCH Filed May 6, 1959 2 h s h 2 INVENTOR. CLAYTONFYFE.

ATTORNEY United States Patent 2,989,600 MOMENTARY CONTACT SWITCH ClaytonFyfe, Milwaukee, Wis., assignor to Badger Meter Manufacturing Company,Milwaukee, Wis., a corporation of Wisconsin Filed May 6, 1959, Ser. No.811,447 Claims. (Cl. '200-30) This invention relates to switches andparticularly to switch mechanism wherein the switch contacts are closedonly momentarily fora constant period of time independent of the rate atwhich the switch is actuated.

It is the object of this invention to provide a switch of this typewhich is of simple construction, reliable and accurate.

This is accomplished by a switch comprising a stationary contact and aresilient switch arm carrying a movable contact mounted on a base withthe switch arm adapted for swinging movement between an unstressed and astressed position to close and open the contacts, respectively. A weightis mounted on the switch arm outwardly from the movable contact andactuating means are provided for imparting uniform increments ofacceleration to the weight to cause the contacts to close and remainclosed momentarily for uniform periods of time.

The actuating means employed may take many forms with the preferredembodiment comprising a resilient actuating arm mounted on the base forswinging movement between an unstressed and a stressed position. Ashoulder formed on the actuating arm is adapted for engagement with theweight as the actuating arm is moved into a stressed position and thenreleased to im part the required acceleration to the weight.

A cam means is provided to disengage the shoulder from the weight as theactuating arm snaps back to its unstressed position permitting theswitch arm to swing freely to close the contacts by the momentum of theweight.

Other objects and advantages will be pointed out in, or be apparent fromthe specification and claims, as will obvious modifications of thesingle embodiment shown in the drawings, in which:

FIG. 1 is a plan view of a switch and actuating mechanism embodying myinvention;

FIG. 2 is a vertical sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a vertical sectional view taken along line 3-3 of FIG. 2; and

FIGS. 4 and 5 are simplified plan views similar to FIG. 1 showing theswitch and actuating mechanism in different operating positions.

Referring now to the drawings, the illustrated embodiment of the switchof my invention includes a stationary contact mounted on a base 12 by abracket 14 with a conductor 16 electrically connected thereto. A movablecontact 18 is mounted on a resilient switch arm 20 which has a conductor24- connected thereto. Switch arm 20 is fixedly secured at one end tobase 12 by a bracket 22 with contacts 10 and 18 normally spaced fromeach other as shown in FIG. 1. Thus, it is seen that by moving arm 20 toclose the contacts a circuit is completed between conductors 16 and 24.

To provide momentary closing of switch contacts 10 and 18 for constant,predetermined periods of time in response to the variable operation of awater meter for example, -I mount a weight 26 on the free end of arm 20outwardly from contact 18 and impart increments of uniform accelerationto the system at a frequency directly proportional to the metering rate.The means for imparting such increments of uniform acceleration may takemany forms. One such actuating arrangement which 2,989,600 Patented June20, 1961 Flce operates very well is shown in the drawings. It includes atoothed ratchet wheel 28 mounted on a shaft 30 extending through base 12which is driven in a counterclockwise direction (as indicated by thearrow in FIG. 1) by the drive spindle of a water meter for example.

Rotation of wheel 28 will cause intermittent actuation of a resilientactuating arm 32 fixedly mounted at one end on base 12 by a bracket 34.Arm 32 has an elongated opening 66 therein through which ratchet wheel28 extends. When wheel 28 is rotated, one tooth thereof will engage edgeportion 38 of opening 36 (FIG. 2) and move arm 32 from the unstressedposition shown in FIG. 1 to stressed position shown in FIG. 4. As arm 32is thus moved a hooked finger 40 extending at right angles at the end ofthe arm 32 is moved into engagement with weight 26 at the end of switcharm 20. A hooked end portion or shoulder 42 formed on finger 40 slidesalong the edge 44 of cam member 46 mounted on base 12 until it is forcedover a lip 48 on weight 26 which is held stationary in its unstressedposition against a stop 50 on member 46.

Continued rotation of wheel 28 from the position shown in FIG. 4 willcause the ratchet tooth to slide off edge 38 and thereby releaseactuating spring arm 32. When this occurs the stored energy in springarm 32 will be imparted to weight 26 causing it to be accelerated in thecontact closing direction from the position shown in FIG. 4 to thatshown in FIG. 5. When the parts reach the FIG. 5 position, hook 42 willbe cammed out of engagement with lip 48 by edge 44 and arm 20 willcontinue to swing freely under the momentum of weight 26 until thecontacts are closed. The momentum of weight 26 will, however, continueto flex arm 20 after initial contact and the contacts will remain closeduntil the direction of movement is reversed causing the contacts tobreak as weight 26 is accelerated back towards stop 50 by the internalresiliency of switch arm 20.

From the foregoing it is seen that the acceleration imparted to weight26 by actuating arm '32 (being independent of the rate at which wheel 28is rotated) will remain constant. Thus, the contact duration for anygiven increment of acceleration imparted to weight 26 will also beconstant making it possible to design a switch suitable for therequirements of a particular application. Furthermore, it is noted thatunder no conditions are the switch contacts in more than momentarycontact, it being impossible for contact to be steadily maintainedregardless of rate or stopping position of ratchet wheel 28.

Although but one embodiment of the present invention has beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

I claim:

1. A switch comprising, a base, a stationary contact mounted on saidbase, a resilient switch arm mounted on said base and adapted forswinging movement between an unstressed and a stressed position, amovable contact mounted on said switch arm, a weight mounted on saidswitch arm outwardly from said movable contact toward the free end ofsaid switch arm, a resilient actuating arm mounted on said base andadapted for swinging movement between an unstressed and a stressedposition, trip means for moving said actuating arm to its stressedposition and then releasing it for snap movement back to its unstressedposition, a shoulder on said actuating arm adapted for engagement withsaid switch arm, and cam means mounted on said base adapted to cam saidshoulder into and out of engagement with said switch arm as saidactuating arm is first stressed and then released by said trip means,said trip means including a toothed ratchet wheel rotatably mounted onsaid base, said actuating arm having an elongated opening thereinthrough which a portion of said ratchet wheel extends.

2. A switch comprising, a base, a stationary contact mounted on saidbase, a resilient switch arm fixedly mounted on said base, a movablecontact mounted on said switch arm and spaced from said stationarycontact, a weight mounted on said switch arm outwardly from said movablecontact toward the free end of said switch arm, and actuating means foruniformly accelerating said weight to cause said movable contact to bemoved into contact with said stationary contact and remain in contacttherewith for a constant period of time, said actuating means includinga resilient actuating arm fixedly mounted on said base and adapted forswinging movement between an unstressed and a stressed position, tripmeans for moving said actuating arm to its stressed position and thenreleasing it for snap movement back to its unstressed position, andengagement means adapted to first establish engagement between saidactuating arm and said switch arm when said actuating arm is in stressedposition and before it is released by said trip means, said engagementmeans further adapted to then release said arms from each other as saidactuating arm snaps back to its unstressed position.

3. A switch according to claim 2 in which said engagement means includesa shoulder on the end of said actuating arm and a cam mounted on saidbase cooperating with said shoulder to earn said shoulder into and outof engagement with said switch arm, as said actuating arm is firststressed and then released by said trip means.

4. A switch according to claim 2 in which said strip means includes atoother ratchet wheel rotatably mounted on said base, said actuating armhaving an elongated opening therein through which a portion of saidratchet Wheel extends.

5. A switch comprising, a base, a stationary contact mounted on saidbase, a resilient switch arm mounted on said base and adapted forswinging movement between an unstressed and a stressed position, amovable contact mounted on said switch arm, a weight mounted on saidswitch arm outwardly from said movable contact toward the free end ofsaid switch arm, a resilient actuating arm mounted on said base andadapted for swinging movement between an unstressed and a stressedposition, trip means for moving said actuating arm to its stressedposition, and then releasing it for snap movement back to its unstressedposition, a shoulder on said actuating arm adapted for engagement withsaid switch arm, and cam means mounted on said base adapted to cam saidshoulder into and out of engagement with said switch arm as saidactuating arm is first stressed and then released by said trip means.

Hall Dec. 15, 1914 Rhoades July 4, 1916

